A packet of cigarettes normally comprises an inner package defined by a group of cigarettes wrapped in a sheet of inner packing material; and an outer package enclosing the inner package, and which may be cup-shaped and made from a sheet of outer packing material folded about the inner package (soft packet of cigarettes), or may be defined by a rigid hinged-lid box formed by folding a rigid blank about the inner package (rigid packet of cigarettes).
In a conventional packet of cigarettes, the group of cigarettes is wrapped internally in a rectangular sheet of foil inner wrapping material with no glue, and is packed externally in a rectangular sheet of outer packing material that is stabilized using glue.
Tobacco is highly sensitive to environment. That is, in contact with the atmosphere, its organic characteristics tend to vary alongside variations in humidity (by losing or absorbing too much moisture) or due to evaporation of the volatile substances with which the tobacco is impregnated (especially in the case of aromatic cigarettes treated with spices such as cloves). To preserve the tobacco, packets of cigarettes are therefore cellophane-wrapped, i.e. wrapped in a heat-sealed overwrapping of airtight plastic material. This, however, may not always be sufficient to fully preserve the tobacco in the packet, especially if the packet is consumed some time after manufacture. Moreover, when the packet is unsealed, the overwrapping is removed, thus exposing the tobacco to the atmosphere, and, if the cigarettes are not consumed soon after the packet is unsealed, the organic characteristics of the remaining cigarettes may deteriorate.
In an attempt to eliminate this drawback, U.S. Pat. No. 4,300,676A1 proposes a rigid packet of cigarettes, in which the inner package is airtight, and comprises a sheet of airtight heat-seal wrapping material having a cigarette extraction opening closed by a reusable cover flap.
It has been observed that folding the sheet of inner wrapping material about the group of cigarettes may damage the ends of the cigarettes and result in localized deformation (of both the filter-tipped and plain ends, i.e. where the tobacco is exposed), and/or tobacco spill (i.e. tobacco fallout, obviously only from the plain ends). This applies in particular to the corner cigarettes in the group, though damage is also evident in all the outermost cigarettes, i.e. located along the fold lines of the sheet of inner wrapping material. Folding a sheet of airtight inner wrapping material is particularly harmful, by being thicker (and therefore stiffer) than conventional sheets of foil wrapping material. Heat sealing the superimposed portions of the sheet of inner wrapping material may also damage the cigarettes underneath, in that, to achieve a good-quality (i.e. airtight) seal quickly (modern packing machines operate at a rate of 500 packets a minute, which means heat sealing must be completed in a fraction of a second), the superimposed portions must be subjected to considerable pressure—which is inevitably transmitted to and may cause permanent deformation of the cigarettes underneath—and must be heated to a high temperature, with the obvious danger of possibly overheating the tobacco in the cigarettes underneath (thus resulting in local drying and alteration of the organic characteristics of the tobacco).
U.S. Pat. No. 3,813,849A1 discloses an automatic packaging machine for macaroni, or the like, in which the machine includes a vertical disposed, rotatable conveyor wheel with adjacent arranged stations for filling, weighting, sealing and closing; the wheel has pockets in the periphery for receiving packaging material and the articles to be packed, and associated with the wheel are folding and closing mechanism for effecting individual steps of the operation.